Electric switch



Feb. 25, 1930.

G. STERN ELECTRIC SWITCH Filed March 16. 1928 Inventor: eorg Stern MW HIS Attorneg Patented Feb. 25, 1930 UNITED STATES PATENT OFFICE GEORG STERN, F OBERSCI-IONEWEIDE, NEAR BERLIN, GERMANY, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCI-I Application filed March 16, 1928, Serial No.

My invention relates to electric switches of the liquid break explosion chamber type and the object of my invention is to provide an improved switch having an explosion chamber which will avoid the danger of an are being established between it and the movable contact.

My invention will be better understood from the following description taken in con nection with the accompanying drawing, and

its scope will be pointed out in the appended claims.

Referring to the single figure of the drawing which is asectional View illustrating an embodiment of my invention, the switch comprises the fixed contact 1 which is a sleeve adapted to receive the movable contact rod 2, the operating means for which is not shown. Contact 1 with which the external circuit connection, not shown, may be made in a manner well understood in the art is enclosed by the explosion chamber 3 and is firmly secured to member l forming the cover of the explosion chamber. The body portion of the explosion chamber is an insulatin cup-shaped member 5, constructed of molded ceramic material, such, for example, as steatite, or fired soap stone. Member 5 is cupshaped in form, being provided with an opening in the bottom adapted to receive the contact rod 2 ant having an enlarged edge 7 by which it is clamped to the cover l by means of the ring 8. For the purpose of protecting the surface of member 5 against direct contact with an are drawn between the circuit contacts 1 and 2 when the switch is being opened I have provided the members 9, 10 and 11, which may be of any suitable insulating material, and have arranged these members so as to cover that portion of the surface of member 5 which is exposed to the are. In certain cases I may prefer to construct the member 5 of glass instead of steatite using a glass which is capable of withstanding the mechanical stresses and high temperature to which it would be subjected as a part of the switch.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In an electric switch of the liquid break 262,286, and in Germany March 30, 1927.

type, a fixed contact, a cooperating movable contact, and an explosion chamber enclosing the fixed contact and having an opening therein for receiving the movable contact, said chamber having the body portion thereof constructed of a single piece of ceramic material.

2-. In an electric switch of the liquid break type, a fixed contact, a cooperating movable contact, and an explosion chamber enclosing the fixed contact and having an opening therein for receiving the movable contact, the body portion of said explosion chamber being constructed of a single piece of steatite.

3. In an electric switch of the liquid break type, a fixed contact, a cooperating movable contact rod, and an explosion chamber enclosing the fixed contact, said chamber comprising a top plate to which the fixed contact is secured, a one-piece cup-like member constructed of ceramic material having an open-- ing in the bottom thereof for receiving the contact rod and means for securing together the top plate and the member of ceramic material.

l. In an electric switch of the liquid break type, a fixed socket contact, a cooperating cont-act rod, and an explosion chamber en closing the fixed contact, he body portion of said chamber being formed of a single piece of ceramic material and having an opening therein through which the contact rod is adapted to be withdrawn after separation from the fixed contact, and insulating means forming a protective cover for the portions of the chamber which are exposed to an are drawn between the contacts.

In witness whereof, I have hereunto set my hand this 24th day of February, 1928.

GEORG STERN. 

